Hormonal changes during a long term isolation (SFINCSS-99 project)
Abstract
Long duration of space mission and functioning in Earth's orbit of the International Space Station make humans put up with spatial constraint for many months. From previous studies, it appears that confinement and inactivity can induce great psychological and physiological modifications by social and sensory deprivation. SFINCSS-99 experiment had the goal to determine the cardiovascular and the hormonal pattern of blood volume regulating hormones responses. Simulation experiments were performed in pressurized chambers outfitted with technical infrastructure including the systems for air regeneration, thermal and humidity air control, power supply, communications, TV monitoring, gas analysis and local electronic network. Three groups of test-subjects were functioning in parallel in adjacent modules, which mocked the ISS Russian and others segments. One33 crew (group I) occupied the 100 m module and the others the 200 m module (II &III). They could communicate and work together. Group I consisted from Russian males- volunteers aged of 37 to 48 who spent 240 days in chamber. Group II included 4 males (one German and three Russians) aged from 27 to 45, spent 110 days in isolation. In blood samples, drawing before, during and after isolation's period hormones were determined, in urine samples - excretion of hormones, electrolytes, nitrites, nitrates, and osmolality. The increase of plasma volume (hematocrit decrease in Group I was 13,2%: 42,7+/-0,5 vs 39,2+/-1,2; p< 0,05; in Group II - 4,1%: 44,3+/-1,0 vs 43,3+/-2,6) in association with a tendency to decrease in plasma renin activity (in Group I 13,1+/-3,5 vs 27,8+/-6,0) was likely to be due to decreased sympathetic activity, this do agree with the changes in urinary catecholamine (CA) during confinement. Urinary CA were significantly higher during the recovery period than during confinement (in Group I 341+/-44 vs 240+/-19, p< 0,05). This suggests that the sympathoadrenal system was activated, and agrees with the increase of heart rate. The ratio of nitrite/nitrate in urine, an indicator of NO release, didn't show significant changes. In this experiment Bystritskaia noted a presence of phase in adaptation process approximately 60 days long, the similar facts were obtained by Gushin V., who showed the presence of about 60-days rhythm of communication activity (oral and written). Analysis of data suggests that duration of isolation was a factor mainly for regulation of hormones but all physiological systems are highly influenced by confinement, which can decrease the capacity for work of the person.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E.303L